Frame joining element



FIG. 1 is a front and left-side, perspective view of a frame joining element showing the design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left-side elevation view thereof;

FIG. 4 is a rear elevation view thereof; and,

FIG. 5 is a top plan view thereof. 

CLAIM The ornamental design for a frame joining element, as shown and described. 